import org.junit.Test;
import static org.junit.Assert.assertArrayEquals;
import java.util.Arrays;

@SuppressWarnings("unused")
public class ExampleUnitTest2 {
    @Test
    public void test2_20ones() {
        int[] expected = new int[20];
        Arrays.fill(expected, 1);
        assertArrayEquals(expected, yourMethod());
    }

    public static int[] yourMethod() {
        int[] arr = new int[20];
        Arrays.fill(arr, 0);
        return arr;
    }
}